In the field of high speed permanent magnet motor, permanent magnets are easily thrown off from a rotor in a radial direction of a shaft by centrifugal force of the rotor while the rotor is rotated at a high speed. Therefore, developers are constantly working on solving the aforementioned problem.
In the conventional permanent magnet motor or alternating-current generator, there are two ways for fixing the magnets to the rotor. The first way is to attach the magnets to the surface of the rotor via adhesive. The second way is to dispose the magnets inside a rotor core of the rotor.